Our Father who are....

[navi]

Our Father who are in heaven, hallowed be thy name.


I have seen the phrase 'Our Father who are in heaven' written both with and without a comma after 'Father'. Would the presence of the comma make any difference? Would it make the clause non-restrictive?
Would the absence of a comma make it restrictive?


Gratefully,
Navi.

[Alan]

Yes, naturally.

(The questions as to which is more appropriate is, however, not an issue of grammar, so I will refrain from commenting!)